He is a member of the Federal Election Commission after President Donald Trump nominated him and the Republican-controlled Senate confirmed him.

[1] He practiced election law, campaign finance, and ethics[2] as a partner in Akerman LLP's Austin office.

[3] After Trump became president, Trainor joined his administration as special assistant to Secretary of Defense James Mattis.

[4] On September 14, 2017, Trump nominated Trainor to be a member of the Federal Election Commission for a term expiring April 30, 2023.

[12] In interviews in September 2020 with the Religion News Service, as well as Michael Voris of the right-wing Catholic website Church Militant, Trainor said that churches could endorse political candidates, contrary to common understandings of the Johnson Amendment, which bars tax-exempt nonprofits from endorsing political candidates.